What's the Matter? Antimatter!

September 4, 2019

Diagram of an antihydrogen atom

 

What is Antimatter? Antimatter is just like ordinary matter (stuff that make most things in the universe like mountains, Earth, stars, and us), but once it comes in contact with matter, they cancel each other out and disappear by releasing energy. This process is called annihilation. Both matter and antimatter have the exact same mass but different electric charges; if an object made of ordinary matter is positively charged, its antimatter counterpart is negatively charged and vice versa.  So just like adding 2 to -2 equals to 0, oppositely charged matter and antimatter annihilate.  

 

The modern theory of Antimatter began in 1928 following the publishing of a scientific paper by Paul Dirac, who predicted the existence of an anti-electron, widely known as the positron.  With the opening of brand new physics, numerous physicists tried to elucidate the properties of antimatter and the implications of its existence as to the nature of our universe. A breakthrough came about in 1995 when research teams from CERN and Germany’s Fermilab succeeded in artificially synthesizing an antihydrogen atom, the antimatter version of a hydrogen atom.  This led to a conclusion that antiparticles (antimatters of the fundamental particles) are formed as a counterpart when energy is converted into particles via high energy collisions. Today, The largest project of this kind is held in CERN’s Large Hadron Collider beauty. Here, antiparticles are created daily and are scrutinized to determine their properties. 

 

CERN’s antimatter factory

 

Crazy stuff… but what is it all for? The grand rationale behind such large scale investigation, in simple terms, is to answer why our universe is the way it is, and how the universe was like right after the Big Bang. Despite these questions being extremely important, such achievements in a frontier field of physics are sadly and often regarded as trivial by the majority of the world.  Therefore, the real question to address is “what will humanity as a whole gain and benefit from such an endeavor?” and “to what extent should we invest our money into fundamental research like the aforesaid?”.  To answer, we shall evaluate the potential impacts of this project together with its limitations and ramifications.  

 

To start with, an enhanced understanding of the nature of antimatter and its cost-efficient production could enable interstellar travel in the future.  We could travel by harnessing the energy produced from matter and antimatter annihilation to propel spacecraft - it would reach near the speed of light.  According to the National Physics Laboratory, matter and antimatter collisions supply 10 orders of magnitude (x1010 or x10000000000) greater energy per unit mass than conventional chemical fuels and 3 orders magnitude greater than nuclear fission.  Thereby, coupled with its high thrust-to-weight ratio and 100% energy conversion rate, antimatter is a strong candidate for future spacecraft fuel to be used in antimatter catalyzed nuclear pulse propulsion and/or in pure antimatter rockets. 

 

 Envisioned design of an antimatter rocket

 

That being said, CERN’s LHCb project is an appropriate opportunity to assess the feasibility of mass-producing antimatter and develop a safe method of storing them. If things go well, antimatter may, in future, lead as the prominent energy source for countless other applications. For airplanes, ships, cars, and  even cities, matter-antimatter annihilation yields the possibility to power our civilization and replace all non-renewable options. However, the greatest benefit of antimatter rocketry comes with its potential to help humanity colonize moons and planets many light-years away from Earth. This brightens up our future as we would be granted access to natural resources in space, though we must first address climate change and resource depletion on our own planet. It would be a shame for us to die before seeing the greater world, and looking into space for a solution is not a practical approach.  So we must first prove ourselves worthy by solving current issues with our wit and dedication. Only then could humanity evolve into a Type 1 civilization; a civilization that harnesses the power of nearby stars.  

 

So far, we have ideas that are exciting but rather far fetched. Our said achievements will certainly take longer than our lifetime to realize. Realistically speaking, the practical applications of antimatter are most anticipated in the field of medical science.  An exemplary spin-off of antimatter technology is the Positron Emission Tomography (PET Scan), a device used to diagnose cancer through medical imaging. Here, Fluorine 19 -  a radioisotope of fluorine - is used. The machine detects pairs of gamma rays that are emitted during the positive beta decay of this fluorine isotope  and thereby maps the density of the cell tissues. Doctors could then locate cancer cells in the patient’s body and proceed to direct treatment. 

 

 PET Scan image identifying lymphoma, a type of cancer (red areas). 

 

The said method is highly effective in detecting cancer of all stages with one of the greatest accuracies among many other procedures.  According to the data collected by the National Center for Biotechnology Information from 2000 to 2002, PET Scan altered diagnostic for approximately seven-tenths of surveyed patients and announced the change of the cancer stage for one-fifth. It further led to identifying severe unexpected conditions in one-twentieth with potentially life-saving ramifications in one-fiftieth.  To build upon this achievement, extensive researches are undertaken to treat certain types of cancer using antiprotons in a comparable method used for the currently existing ion/hadron therapy. Today, scientists are aiming to design and construct a machine that can produce a condensed beam of energetic antiparticles. Such a stream of high energy could disrupt the DNA configurations of the cancer cells and ultimately kill them.  When successfully implemented, this would allow the antiparticles to directly annihilate with the cancer cells and thereby eliminate cancer without leaving a trace. Advanced research on antimatter and its applications could thus establish a precise and complete treatment of cancer, consequently diminishing the frequency of painful deaths and extending average life expectancy. 

 

Despite these wonderful prospects, some challenges need to be met to allow the said scenarios to come true.  To start with, the mass production of antiparticles is still extremely expensive and furthermore a time-consuming process.  According to CERN, 1 gram of antimatter contains approximately 90,000 GJ or 25 million kWh of energy.  Furthermore, to create antimatter requires energy that is 1 billion times greater than its mass.  For particles that travel at near the speed of light, mass is essentially equal to energy (E = mc2), and to synthesize a gram of antimatter roughly requires 25 billion million kWh of energy! Coupled with the electricity bills to run the necessary equipment, the total cost of such mass production would be extremely, unrealistically high.  Besides, CERN stated that even if they dedicate all their accelerators to create antimatter, they would only be capable of producing roughly 1 billionth of a gram per year.  Hence the mass production of antimatter is unfortunately impossible with our current technology, let alone power a rocket that can take us to the nearest solar system. 

 

Another drawback with antimatter is the amount of energy and engineering effort required to store them in isolation.  When antimatter comes in contact with its matter counterpart, they annihilate, meaning all its mass is converted into energy in a cataclysmic bang. Therefore antimatters produced in the accelerator must be carefully stored to separate them from any matter to preserve its mass.  To do this, CERN uses the Penning-Malmberg Trap, which is a method of manipulating the magnetic field into a bathtub shape to trap the charged antimatters inside a vacuum. 

 

 Oversimplified model of a container with penning malmberg trap

 

To operate this device requires a superconducting bipolar magnet, and it requires a continuous, substantial supply of electricity. Thus in the long history of CERN, they have only managed to capture 10 nanograms of antimatter ,since to store more requires more electricity.    

 

All the while, the detriments of antimatter further stem into the field of morals and ethics.

 

During the Cold War, the US-funded studies of antimatter to ultimately create a powerful triggering mechanism for nuclear weapons using antimatter and matter collision.  However, this idea has been developed over the years and the US has now taken interest in antimatter itself to serve as the actual explosive. Once realized, its atrocity would inflict harm upon all of Earth’s population.  With this being said, we must consider the ethical implications of any scientific investigations in an attempt to avoid the misuse of new technology. However, as antimatter can only be produced in certain locations in very small quantities, we still have a long time before antimatter can be of any use to the military. 

 

With all the above points considered, it is virtually impossible to mass-produce antimatter with our current technology on a scale that would allow some of the aforementioned breakthroughs to be realized. This is mainly due to its extreme cost of production that is guaranteed to outweigh the potential profit and the technological development that it will bring about. It would be impossible to justify such spending to the 22 member states who fund CERN’s research expenses from their GDP.  Also, we have yet to establish regulations concerning the applications of antimatter for our safety.

 

Notwithstanding, there are no rational reasons to defund the mentioned endeavors either because projects like the LHCb certainly yield potential to help realize these breakthroughs in the distant future.  We only know so little about antimatter, and the only way in which we can determine its utility is by conducting experiments that aim to further understand its physical properties and consequences. The odds of having another medical spinoff is considerably high.  This is because cancer treatment and other medical procedures do not require a large quantity of antimatter, and it is therefore feasible. All in all, we must continue to make strides, small or large, within the feasible technical, economical, and environmental boundaries while ensuring safety.  These baby steps would slowly but surely accumulate and someday enable us to achieve what we now perceive as pie in the sky science fiction. Until then, our job as scholars is to pass on our understanding of the universe to young people and simultaneously add new entries to humanity’s list of discoveries.

 

 

Title credit to Khafiz Azizov

 

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